Recreational marijuana use could be legal in Arizona by this summer if the Legislature and Gov. Doug Ducey approve a plan introduced by a Phoenix lawmaker.

The legislation will be a long shot under the conservative-led Legislature. But Rep. Mark Cardenas, D-Phoenix, said he has some strong arguments. Among them is the possibility of nearly $50 million in potential tax revenue that could offset a looming $1 billion budget shortfall.

Proponents of legalizing marijuana are expected to try to get a measure on the 2016 Arizona ballot, following similar successful efforts in Colorado, Washington and Oregon. Cardenas said polling in Arizona shows such a ballot measure would likely pass, as medical-marijuana legalization did in 2010.

For a variety of reasons, Cardenas said, it would be better if the Legislature passed its own version of the law first.

"We've seen issues with our medical-marijuana system ... but it's nearly impossible to come back at the Legislature and adjust it because we need 75 percent of the Legislature (to approve any changes to a voter-approved measure)," he said. "This would give us more leeway. If there were unforeseen consequences, we could easily come back and adjust it the next year."

He said going through the Legislature makes sense given the likelihood of voters passing it.

"We have to be smart about governing," he said. "If it's going to happen, let's get ahead of it and make sure we have the conversations to come up with the best program possible."

House Bill 2007 would legalize the purchase, possession and consumption of up to one ounce of marijuana for adults age 21 and older. It would expand the current medical-marijuana system under the Arizona Department of Health Services, and create a process for dispensaries to serve the general public. It would also allow adults age 21 and older to grow up to five plants for personal consumption.

"We have a rough framework to work off of, which would be Colorado," Cardenas said. "We would like to start with a discussion and work towards creating the same system here. They've gained a lot of revenue from that."

HB 2007 would levy a new tax against marijuana, at $50 an ounce. Thirty percent of the revenue would go to education; 10 percent to treatment programs for alcohol, tobacco and marijuana abuse; 10 percent for public-education campaigns educating youth and adults about the risks of alcohol, tobacco and marijuana; and the rest would go into the general fund.

"One of the things that isn't addressed in Colorado that is addressed here is that some of the revenue would be required to fund treatment programs for substance abuse," Cardenas said.

An analysis last year by the Joint Legislative Budget Committee estimated marijuana taxed at this level could bring about $48 million a year into the state.

The proposed tax rate is lower than that in Colorado, but higher than in Oregon. Oregon taxes marijuana at $35 an ounce. Colorado has a 15 percent excise tax, plus a 10 percent sales tax on marijuana, plus regular state and local sales taxes.

HB 2007 will need several legislative committee hearings and votes before it could become law. Even getting a first committee hearing could prove challenging.

A similar bill introduced last session by former Rep. Ruben Gallego, D-Phoenix, now a U.S. congressman, was never assigned to a committee. Without that assignment, it got no hearings or votes.

Cardenas introduced a bill last year that would have lowered the penalties for marijuana possession. It was assigned to the House Judiciary Committee, but Chairman Eddie Farnsworth, R-Gilbert, never scheduled it for a hearing.

Cardenas said he has reached out to Farnsworth about this bill.

"He's mentioned being open to discussion on this, so we're looking forward to getting a hearing," Cardenas said. "The possibility of it passing is not good, but we need to start looking at new and exciting ways to fill our budget gap if the governor is taking a 'no new taxes' stance."